Embodiments of the present invention relate to a thin film transistor liquid crystal display.
Thin film transistor liquid crystal displays (TFT-LCDs), which are of small volume, light weight, low power consumption and free of radiation, have prevailed in the market of flat panel display devices. Recently, with the development of large-sized TFT-LCDs, display panels of larger size with high display quality are required, and also the area of each pixel of such kinds of display panel has become bigger. However, since the area of each pixel is increased, a defective pixel may have a greater impact on the display quality, that is, one bright spot or dark spot may exert a remarkable and adverse influence on the display quality. Therefore, in large-sized TFT-LCDs, it is necessary to reduce occurrence of defective pixel and improve the reliability of each pixel.
Generally, a TFT-LCD comprises an array substrate and a color filter substrate facing with each other and holding a liquid crystal layer therebetween. By applying a common voltage to a transparent electrode on the color filter array and a data voltage to a pixel electrode of each pixel on the array substrate, the orientation of the liquid crystal molecules in the liquid crystal layer can be changed by the electric field generated between the array substrate and the color filter substrate. Furthermore, the intensity of the electric field can be modified by the data voltage, and thus the twist angle of the liquid crystal molecules can be controlled and the amount of transmitted light can be correspondingly controlled for displaying image.
FIG. 6 is a schematic view showing a conventional array substrate. As shown in FIG. 6, a plurality of data lines 1 and a plurality of gate lines 2, which are perpendicular to and insulating from each other, are formed on the array substrate, and a plurality of pixel units are defined by intersecting the gate lines 2 with the data lines 1. A thin film transistor (TFT) 4 serving as a switch device is formed at each of the intersections between the gate lines 2 and the data lines 1, and the TFT 4 is connected with a pixel electrode 5 provided in each pixel unit. A storage capacitor 6 is formed by overlapping the pixel electrode 5 with the gate line 2. However, in the conventional array substrate, the capacitance of the storage capacitor is decreased when a displacement is generated between an upper layer and a lower layer, and therefore the stability of the storage capacitor 6 is low, which tends to bring about a bright spot or a dark spot on the final panel, and there is no effective method to repair the defective spot at present. If a bright spot is generated, such bright spot generally can be converted into a dark spot by a laser repairing method, but the display quality still degrades. Furthermore, light leakage causing by a black matrix may occur due to the errors generated at the time of attaching the array substrate to the color filter substrate and the like.